This reverts commit 61b927af.

Fix issue 4893: After being re-invited in a chat room, when the device is restarted nothing can be done in the chat room.

Store the conference created event in DB and update the notify id in DB if insertion of the chat room is requested but it is already stored.

Delete client group existing one-to-one chat rooms at start-up to use basic chat rooms instead for the moment.

This reverts commit f2910f7d.

This reverts commit 2686dca6.

This reverts commit d7890dbe, reversing
changes made to e6158d8d.